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Old 07-26-2009, 12:58 PM   #1 (permalink)
Piwoslaw
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Location: Warsaw, Poland
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Svietlana II - '13 Peugeot 308SW e-HDI 6sp
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Roofline/Kammback transition - sharp or rounded?

Say the roofline in the back of a car is more or less level (black). Should the Kammback abruptly start dropping at a 11 degree angle (green), or should there be a rounded transition first (red)? (The angles are exaggerated)



Intuition whispers that the sharp edge between roof and Kammy would cause detactment of airflow (blue):



while a rounded transition would help guide the airflow smoothly down the Kammback:



On the other hand, maybe intuition isn't always the best tool in aerodynamics, and maybe the 11 degree angle isn't enought to detach airflow?

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